Dry Shippers Handling

Before Reusing a Dewar

• Inspect the inside of the dewar.

• If there is any sign of ice, do not use it.

• If the dewar is fully thawed, run the air dryer for a few hours to ensure the interior is completely dry before cooling again

Handling and Filling Dewars

• Never open the LN2 valve and leave the dewar unattended while filling.

• LN2 splashing—especially on the vacuum plug—can damage the vacuum seal and gradually reduce the dewar’s ability to hold cold. The damage may not be immediate but will appear after repeated use.

• Avoid rushing experiments. Do not fill a dewar with LN2 and immediately begin harvesting and loading puck - best practice is to fill the dewar with LN2 the day before harvesting so the absorbent material has time to fully soak the liquid nitrogen.

• Ensure the blue foam protector is installed on the vacuum plug

• Before inserting the fill hose into the dry shipper, allow LN₂ to flow for a few seconds outside

• Begin filling the dry shipper with LN₂ and adjust the flow rate as needed to minimize splashing and boil-off

• Fill it up to half of the neck

• In parallel, fill the long blue foam dewar with LN₂

• Place the warm puck holder into the blue foam dewar to pre-cool it

• Once boiling and splashing have subsided, carefully transfer the cooled puck holder into the dry shipper

• Place the lid gently on top and allow it to float.

• Do not push it down, as this can cause LN2 to splash onto the vacuum plug

Before Adding your Unipucks

• Check the LN2 level.

• Inspect the dewar for warning signs such as sweating, frost, or ice on the exterior.

During Storage Before Beamtime

• After loading your pucks, if your beamtime is several days away:

• Check the LN2 level every 3–4 days and refill with LN2 as needed - If the liquid level rises very high in the neck:

Shipping Dewars

• Before shipping, remove all excess LN2. Liquid nitrogen is hazardous during transport.

• Do not forget to add the locking rod as the pucks can move during shipping and get stuck inside – this will cause losing the crystals / we will have to cut the dewar open to save the pucks and loops

• Carriers will return the shipment if LN2 is present.

• Daily pickups occur at 3:00 PM from Genentech Hall - checking shortly after 3:00 PM to confirm your dewar was picked up and if it was not picked up, return it to the facility and contact the beamline scientist to plan accordingly.

• You can drop off your dewar before 5:00 PM at this fedex office location: 1155 Harrison St, San Francisco, CA 94103

It's always good to scan this checklist quickly before every experiment to make sure to not miss any detail

Thank you